Should you repair or replace an apartment water heater?
Repair when the fix is small and the tank is sound; replace when the tank itself is leaking or when the repair costs more per remaining year of life than a new heater costs per year. Add the cost of another outage to the repair side, because a tenant without hot water is a legal and a cash problem. Then record the choice correctly: a repair is usually an expense now, while the IRS lists a water heater as an example of an improvement that is depreciated.
Three quick rules before any math
- A leaking tank is a replacement. Parts like thermostats, elements, igniters, gas valves and relief valves can be swapped; a rusted-through tank cannot.
- A safety part is never skipped. If the temperature and pressure relief valve is suspect, it gets replaced now, whichever way you go.
- A unit with no hot water gets service back first and the decision second. In Washington, for example, repair of a defect that cuts off hot water must begin within 24 hours of notice (RCW 59.18.070), and New York City requires 120°F hot water all year (NYC HPD).
The cost per remaining year method
Most repair or replace decisions come down to one comparison. Divide what each choice costs by the years of service it buys, then add what a failure would cost you on the repair side.
- Get the repair quote and ask the plumber how many more years the tank is likely to last with that repair. Write their estimate down; it is a judgment, not a fact.
- Get a replacement quote, installed, including haul-away and any code updates the installer says are needed.
- Ask the installer how many years the new unit is expected to last in your conditions.
- Repair cost per year = repair quote / years left. Replacement cost per year = replacement quote / expected life.
- Add the expected cost of a surprise outage to the repair side: emergency call premium, any hotel or rent credit, and your time.
- Pick the lower number, unless a safety or compliance issue settles it first.
A worked example
Example a made-up 8 unit building has one shared gas water heater. The igniter and gas valve have failed. Repair quote: $650, and the plumber thinks the tank has about 2 more years. Replacement quote: $4,200 installed, expected to last about 12 years. Repair per year: $650 / 2 = $325. Replacement per year: $4,200 / 12 = $350. On cost alone, repair wins by $25 a year. But the owner estimates that if the old tank fails without warning in the next 2 years, an after-hours call and one day of rent credits for 8 units would cost about $900, and judges that about even odds. Expected outage cost: $900 x 0.5 = $450, or $225 a year over 2 years. Repair now costs $325 + $225 = $550 a year against $350 for replacement, so the owner replaces.
The numbers are made up, and your plumber's estimates will differ. The point is the shape: a cheap repair on an old tank often loses once you count what a surprise failure costs in an occupied building. A single unit's heater, where an outage affects one household, tips the other way more often than a shared one.
| Line | Repair | Replace |
|---|---|---|
| Quote | $650 | $4,200 |
| Years of service | 2 | 12 |
| Cost per year | $325 | $350 |
| Expected outage cost per year | $225 | $0 (new unit) |
| Total per year | $550 | $350 |
How each choice is booked
For taxes, the two choices land in different places. IRS Publication 527 says an expense is for an improvement if it results in a betterment to your property, and its table of improvement examples lists a water heater under plumbing. Improvements are depreciated, not deducted all at once (IRS Pub 527). Swapping a failed igniter is the kind of repair that keeps property in working order and is usually deducted in the year paid.
The IRS tangible property rules also offer safe harbors that can let some costs be deducted, such as the de minimis safe harbor of up to $2,500 per invoice or item for owners without an applicable financial statement, and a routine maintenance safe harbor for buildings (IRS). Our post on the de minimis safe harbor explains it. Your tax preparer makes the final call, so keep the invoice and a note on what was done.
Make the next decision easier
- Label every water heater with its install date and the units it serves.
- Keep a log of every service call per heater. Three calls in a year is a signal.
- Put shared heaters into your capital reserve plan with a replacement year.
- Know where each shutoff valve is, and make sure your on-call vendor does too.
In DoorKeeping
DoorKeeping keeps repairs and improvements in separate accounts in each property's books, which is exactly the line this decision turns on: a new heater is usually an improvement, a new thermostat a repair. You can ask your AI app what a building has spent on repairs this year before you decide, and approving the invoice waits for your tap. DoorKeeping prepares numbers; your tax preparer decides the tax treatment.
Sources
- IRS, Publication 527, Residential Rental Property, read Oct 29, 2026
- IRS, Tangible Property Final Regulations, read Oct 29, 2026
- Revised Code of Washington 59.18.070, read Oct 29, 2026
- NYC HPD, Heat and Hot Water Information, read Oct 29, 2026
Questions
- Is a new water heater a repair or an improvement for taxes?
- IRS Publication 527 lists a water heater as an example of an improvement, which is generally depreciated. A safe harbor may change that in some cases, so ask your tax preparer.
- When should a water heater be replaced instead of repaired?
- Replace it when the tank leaks, or when the repair costs more per remaining year of life, including the risk of an outage, than a new unit costs per year.
- How fast must a landlord restore hot water?
- It depends on where you are. Washington requires repairs that restore hot water to begin within 24 hours of notice; New York City requires 120°F hot water all year.